(NH)-Phosphanylamido- and (PH)-Phosphoraneiminato Transition-Metal Complexes: Syntheses, Structures, and Computational Studies

Reactions of aminobis(diorganylamino)phosphanes (R 2 N) 2 PNH 2 (R = i Pr ( a ), Cy ( b )) with Cp 2 MCl 2 (M = Ti, Zr, Hf), CpTiCl 3, and TiCl 4 lead to the formation of the transition-metal complexes (R 2 N) 2 PN(H)MCp 2 Cl (M = Ti ( 1b ), Zr ( 2a, b ), Hf ( 3a, b )) (R 2 N) 2 P(H)NTiCpCl 2 ( 8a, b ), and (R 2 N) 2 P(H)NTiCl 3 ( 10a, b ), respectively. The influence of electronic effects of the metal fragment on the resulting equilibrium between the (NH)-phosphanylamido and the tautomeric (PH)-iminophosphorane form is presented in detail. Computational studies unambiguously confirm the experimental results. The molecular structures of 2a, 3a, and 8b have been determined by single-crystal X-ray diffraction.